Typical US type race engines utilizing wet sump oil pumps, (pump in pan) effectively use the basic design supplied by OEM engine manufacturers. These pumps are typically driven at ½ engine speed by various drive devices powered by the camshaft. These OEM engines typically have a max rpm range of 5,000-7,000 rpms and thus, the pumps typically have a max rpm range of 2500-3500 rpms (i.e., ½ the engine range). When used in high rpm (8-9000) race engines, engine builders find the OEM style oil pumps pump oil at excessive pressures, causing among other issues, oil cavitation, foaming and power pumping loss. Presently, this is addressed by regulating the pump's output with a bypass valve, which in most cases, engages at between 2000-3,000 engine rpms.
Additional issues with wet sump oil pump systems is oil starvation due to high “G” acceleration and deceleration forces that move the oil in the pan so violently that the pump pickups are often uncovered and can no longer supply oil, causing bearing failures.